Rigid endoscope system

Abstract

A rigid endoscope system includes: a pipe body; an objective lens; an ocular lens; an image pick-up sensor; a light source that emits a detection light to an object to be observed; a light receiving sensor that receives the detection light reflected by the object to be observed and has passed through the inside of the pipe body; a spectroscopic device that spectrally disperses a luminous flux emitted from the ocular lens in each of a direction toward the image pick-up sensor and a direction toward the light receiving sensor; a unit that calculates a distance to the object to be observed; an image-forming system that forms an image of a portion of the luminous flux on the image pick-up sensor; and a focus adjustment unit that performs a focus adjustment by moving a lens included in the image-forming system in an optical axis direction based on the calculated distance.

What is claimed is: 
     
         1 . A rigid endoscope system comprising:
 a linear pipe body;   an objective lens provided at one end side of the pipe body;   an ocular lens provided at the other end side of the pipe body opposite to the one end side thereof;   an image pick-up sensor configured to output an image pick-up signal for generating image data;   a detection light source configured to emit a detection light to an object to be observed;   a light receiving sensor configured to receive the detection light that is reflected by the object to be observed and has passed through the inside of the pipe body;   a spectroscopic optical device configured to spectrally disperse a luminous flux emitted from the ocular lens in each of a direction toward the image pick-up sensor and a direction toward the light receiving sensor;   a calculation unit configured to calculate a distance to the object to be observed by measuring time taken from emission of the detection light from the detection light source to reception thereof by the light receiving sensor;   an image-forming optical system configured to form an image of a portion of the luminous flux emitted from the ocular lens on the image pick-up sensor; and   a focus adjustment unit configured to perform a focus adjustment by moving a focus adjustment lens included in the image-forming optical system in an optical axis direction based on the distance calculated by the calculation unit.   
     
     
         2 . The rigid endoscope system according to  claim 1 , wherein an illumination light for illuminating the object to be observed is used as the detection light. 
     
     
         3 . The rigid endoscope system according to  claim 2 , wherein the spectroscopic optical device is a half mirror. 
     
     
         4 . The rigid endoscope system according to  claim 1 , further comprising an illumination light source configured to emit an illumination light for illuminating the object to be observed, wherein
 the detection light is superimposed on the illumination light and projected on the object to be observed.   
     
     
         5 . The rigid endoscope system according to  claim 4 , wherein
 the detection light is an infrared light, and   the spectroscopic optical device is a beam splitter configured to spectrally disperse the luminous flux into a visible light and an infrared light.   
     
     
         6 . The rigid endoscope system according to  claim 1 , wherein
 at least a part of the pipe body is replaceable by one of a plurality of replacement pipe bodies having optical wavelengths different from each other; and   the calculation unit calculates the distance using a correction value corresponding to the replacement pipe body with which the part of the pipe body has been replaced.   
     
     
         7 . The rigid endoscope system according to  claim 1 , wherein the focus adjustment unit corrects a moving position of the focus adjustment lens based on a contrast evaluation value of an image of the object to be observed calculated from the image pick-up signal.